Method of strengthening receiver-shells.



UNITED STATES PATENT OFFICE.

JOSEPH B. EDWARDS, OF CHICAGO, ILLINOIS, ASSIGNOB TO KELLOGG SWITCHBOARDAND SUPPLY COMPANY, F CHICAGO, ILLINOIS, A CORPORATION 0F ILLINOIS.

METHOD OF STBLENGTHENING RECEIVER-SHELLS.

Specification of Letters Patent.

Application led March 9, 1910, Serial No. 548,197. Renewed January 3,1911. Serial No. 600,526.

T0 all whom. lit may concern.'

Be it known that l, JOSEPH B. EDWARDS, a citizen of the United States,residing 1 n Chicago, county of Cook and State of Illi- 5 nois, haveinvented certain new and useful Improvements in Method of StrengtheningReceiver-Shells, of which the following 1s a specification.

My invention relates to means for 1o strengthening articles formed ofhard rubber or articles formed from various compositions used as asubstitute for hard rubber.

The invention is particularly adapted for use in strengthening telephonereceiver shells which are made of insulating matethey combine withlightness a high degree of strength, so as to resist breakage fromdropping or severe knocks and general rough handling to which any deviceused by the public is subjected. Hard rubber or the various compositionsthereof are demanded for this class of work because of the highinsulation of such material and because it is susceptible of a highfinish, but such material has the undesirable quality of being 'ifragile, and easily chipped or broken. This is a source of great expenseto telephone operating companies having large numbers of telephonereceivers in use.

I provide convenient means for manufacturing the receiver shells and earpieces of hard rubber or composition which has the desirable qualitiesas to insulation and finish demanded by telephone users withoutrendering the parts liable to become broken 4o by careless handling andwithout adding weight to the receiver to obtain this additionalstrength. This result is accomplished by coating a thin metallic supportwith a thin layer of the hard rubber or com )osition that is toconstitute the exterior finish of the parts.

I have illustrated the preferred forms of my invention in theaccompanying drawing, in which- Figure 1 is a plan view of one way ofconstructing the metallic support. Fig. 2 is a-sectional view of themodification of Si showing the metallic support coated with hard rubber,and showing the ear cap in section. Fig. 3 is a plan view of themetallic sup ort shown in Fig. 1 before being molded into shape. Figs. 4and 5 show modifications of the metallic supporting member.

The receiver shown in Figs. l, 2 and 3 consists of thin sheet metal fromwhich portions are stamped out forming slotted apertures 1, which permitthe insulating material 2 to nnite`from the two sides of the receivershell and firmly adhere to the metal as shown in Fig. 2. In this form,the metal support is preferably constructed with interlockin bayonetoints 3, the metal being first per orated an formed as desired in a flatsheet. It is then rolled into shape, the bayonet joints locking thejoining edges of the metal, and uniting it into a continuous cylindricalform. The composition or hard rubber compound is then applied in a thinlayer on both sides of the metal support and vulcanized. In vulcanizingthe rubber contained in the compound, it unites through theperfor-ations or other openings in the metal support so as to form aperfectly homogeneous mass completely covering the article and lirmlysecured thereto at all points through the perforations or openings inthe metal support. In receiving an excessively sharp or hard blow therubber may crack slightly, but will not chip oil' an mar the appearanceof the device. The support for the ear cap is preferably a perforateddisk or ring 4.

In the modification shown in Fig. 4 a long metallic band or ribbon iswound upon a suitable form and secured at its ends. This spiral form orribbon is then coated with the rubber insulating material, which firmlyunites from the two sides, and adheres thereto through the helica of thecoil.

In Fig. l have shown a single piece of tubing having apertures cut orblocked out therein as a support for the insulating rubber compound ofthe receiver.

What I claim as new and desire to secure by Letters Patent is:

A telephone receiver shell consisting of a thin strip or strips of sheetmetal containlng perforations, suitable means arranged along thelongitudinal edges of said strips of metal for securing sai edges whenthe strip or strips of sheet metal are rounded Signed by me ut'Chicngo,county of Cook, into oyllndrical form, und a coating of hard und Stuteof Illinois, in the presence ot two rubber or lnsulatln compounddisposed witnesses.

upon the exterior ot the cylindrical shell JOSEPH B. EDWARDS. thusformed, the pcrforutions in snid metal Witnesses:

assisting to secure said insulating compound Gronau E. MUELLI-m,

securely in position thereon. BEssm OBRIEN.

Copies of this patent may be obtained for iive cents each, by addressingthe Commissioner of Patents,

Washington, D. C.

